Large-area light sources are well known and used, for example, to illuminate flat, transparent indicators such as dials behind which a pointer may move and, also LCDs. Generally, the light sources are formed in plateform of light-transmissive material, having a narrow edge surface which is exposed to light from a prime light radiating device, such as an incandescent lamp or the like. The light is reflected within the plate itself and thus causes the entire plate to emit light at the major planes or surfaces thereof.
When used in combination with an LCD, light is introduced at one of the narrow side surfaces, generated by a small incandescent lamp, and is emitted from one of the major plane surfaces of the plates through the LCD display.
Large-area light sources have, generally, the disadvantage that the density of light emission, that is, the lumens per cm.sup.2 from the flat plane surfaces of the light source, is non-uniform. Light sources of this type provide output displays which are frequently not suitable for many uses since the non-uniform brightness of the background display may result in insufficient illumination of areas which should be illuminated, thus leading to misreading of information which is to be displayed by the LC display array.